Typically, when interconnecting access networks running a routing protocol (e.g., Open Shortest Path First (OSPF), Border Gateway Protocol (BGP), Routing Information Protocol (RIP) or the like) over a shortest path bridging (SPB) Core, using native Internet protocol (IP) shortcuts or L3VSNs, a router may be required to redistribute routes from a first routing protocol to a second routing protocol. For example, a router may be required to redistribute IP routes from OSPF/RIP into Intermediate System to Intermediate System (IS-IS) (IP) and redistribute from IS-IS (IP) into OSPF/RIP. When redistributing routes from a first routing protocol to a second routing protocol a potential may exist for a routing loop to be created.
With some conventional networks, a user may need to manually configure any route policies specifically for the purpose of avoiding routing loops in a particular topology (e.g., a shortest path bridging, or SPBM, network). In some conventional networks, a need may also exist to alter the route preference values of routing protocols for the purpose of avoiding routing loops.
Route-policies are typically static and can cause undesired effects in certain scenarios. For example, if a user seeks to avoid routing loops in a topology such as that shown in FIG. 1, using route policies, then a route policy may need to be configured on backbone edge bridge multi-chassis link aggregation group topologies BEB 1 102 to include “do not install 192.168.10.0/24 prefix from BEB 2 104 via ISIS protocol.” Now, suppose the OSPF process crashes on BEB 1 102, which can cause there to be no OSPF session from BEB 1 102 to BEB 2 104 and node 106. However, BEB 2 104 still has an OSPF session with backbone core bridge BCB 108 and learns about 192.168.10.0/24 via OSPF and redistributes via ISIS to BEB 2 104, but BEB 1 102 would not install the route because of route policy, even though there is a path available from BEB 1 102 to node 106 via BEB 2 104.
Embodiments were conceived in light of the above-mentioned problems and limitations, among other things.